A suicide car bomber attacked a market in southern Afghanistan Sunday, killing at least 13 people and wounding many more.

The attack in Helmand province's Nawa district targeted a military convoy, local officials said. Most of the victims were Afghan soldiers and police personnel.

The Afghan Taliban claimed responsibility for the attack.

In the past two years, and after the withdrawal of most foreign combat troops, the Taliban have stepped up attacks and spread out from their southern heartland across the country. Attacks in the north have also increased.

Government forces took control of the district from the Taliban last month, but fighting has continued. The Taliban still control several districts in Helmand, the largest Afghan province that shares its borders with Pakistan and Iran.

Sunday's attack followed another suicide attack last week in the provincial capital of Lashkar Gah, where a bomb explosion killed seven people and wounded 40 others.

In a separate incident on Sunday, two police officers, including a district police chief, were killed in western Nimroz province when their convoy was attacked by militants, a provincial official said.